Oy Vey! Hand me the lariat so we can lasso this idée
The plain facts are these:
To succeed outside of an insular community in the US (ie. "Chinatown", "Little Havana", "Little Berlin", etc.), you must be able to communicate in English. In fact, English has become the most common language used in both business and travel around the world.
Although there is no "official" language of the United States, most proceedings in the public, governmental, and business sectors are conducted in English. Anyone who cannot speak the language is at a severe disadvantage. Anyone who cannot speak English
well is at significant economic disadvantage. We do have enclaves where public proceedings are conducted in the language of the majority of local citizens, but translation into English is generally required for the outcome of those proceedings to be filed with other levels of government, or to enter the public record.
Does this mean that radio stations that broadcast in another language are harmful? I don't think so. We have a significant population of citizens who do not speak English well enough to understand information from the mainstream media. In fact, one of the dangers is the control of information by non-English outlets with an agenda that warps the presentation of ideas. Multiple non-English media outlets with differing points of view is a bonus, not a negative.
Usually, within a generation, people are at least bi-lingual, and within a couple of generations English is the dominant language. The only way to assure this would be to create an American version of
L'Académie Française to protect the "purity" of American English. I can think of nothing that would be less American.